Disk grinding-machine



W. A. LORENZ. DISK GRINDING MACHINE. APPLICATION FILED MAR. I7, |919. 1,355,345. Patented Oct. 12, 1920.

State of 'useful Improvements in Disk Grinding-Ma- I' UNITED STATES PATENT OFFICE.

DISK GRINDING-MACHIN E.

Specification of Letters Patent.

Application ied March 17, 1919. Serial No. 283,165.

To all whom t may concern.

B'e it known that I, WILLIAM A. LORENZ, a citizen of the United States residing at Hartford in the County of Ifartford and onnecticut, have invented new and chines, of which the following is a specification.

This invention relates to the construction" of the rotatable heads of grinding machines to which abrasive disks are held by atmospheric pressure.

The object of the invention is to provide `a head for such machines which is simple and cheap to manufacture and to which the abrasive disks can be easily and irmly secured for work and quickly released for changing the position of partly worn disks or substituting new disks for those which have become worn.

Figure 1 of the accompanying drawings shows a side elevation, with parts in central section, of a disk grinding machine provided With a head that embodies the invenform. Fig. 5 is a view of -a form of clamp that may be used.

In the machine illustrated a hollow shaft 11 is mounted in bearings 9 and 10 on thetop of the frame 8. This shaft bears a pulley 14 adapted to be driven by a belt 15. Surrounding the shaft is a fixed collar 20 and communicating between the interior of the shaft and the chamber 21 in the collar are holes 19. Leading from the chamber is a pipe 22 which is designed to be connected with a vacuum pump.

Near the threaded end 13 of the shaft is a collar 12 and screwed on this end of the shaft is the hub 28 of the head 25. This head is circular in .outline and has a closed outer edge 26 andan inclined back 27.

Through the center of the head is a perfo-l ration 29 which is crossed by a bridge v30 leaving openings 31 on each side of the bridge. In thel front face of the head are recesses 34 which extend from the central perforation outwardly to'near the closed outer circumference of the head. These recesses may extend radially as shown in Fig.

3 or spirally as shown in Fig. 4 and they are preferably made deeper and narrower at the center, asat 35 Fig. 3 and 47 Fig. 4, than at the outer end, as at 36 Fig. 3 and 48 Fig. 4. Inside of the outer closed circumference of the head the outer ends of these recesses are connected by grooves 37. The inner ends 40 of the lands 45 which are between the recesses are desirably beveled off toward the central perforation. In this tapering central opening is a cupshaped sheet metal clamp 4l, the outside wall of which is inclined approximately at the same angle as that of the beveled ends of the lands. This clamp is held in position by a bolt 43 which screws into a threaded opening in the bridge 30 across the central perforation through the back of the head. The edge of the clamp and thehead of the bolt are below the plane of the front face of the head so as not to interfere with Patented oet. 12, 1920.

the Work when the clamp is employed to I hold the center of an abrasive disk to the face of the head.

When an abrasive disk 49 is held to the head by exhausting air from the recesses back of it, the sections of the abrasive backed by the lands will do substantially all of the work, while the intervening sections will be sucked inward between the lands and escape wear. As soon as the sections of the abrasive in front of the lands become ineHective the vacuum may be released and the clamp loosened, then the disk may be rotated so that the unworn sections of abrasive will come in front of the lands and the worn sections between the lands. In this manner all 0f the abrasive on the face of the disk may be fully utilized, and vfurthermore the drawn-in sections of the disk act as dust receptacles so that grit is not driven into the work. iThe clamp closes the central opening in the abrasive disk so that the necessary vacuum may be obtained back of when the head is rotating and the suction is relieved.

The invention claimed is t- 1. A grinding machine having a rotatable head, said head having a closed outer edge,

channels in its frontv face vextending from the center outwardly and terminating inside of the closed outer edge, and an openq ing through its back near the center and' communicating with said channels, through which air may be exhausted from said channels when an abrasive disk is placed on the front face of the head over the channels.

2. The machine described by claim 1 characterized by having said head mounted on a rotatable hollow shaft7 the opening in which communicates with the opening through the back face near the center of the head.

3. The machine described by claim 1 characterized by having the channels in the front face of the head narrower and deeper near the center than near the outer edge of the head.

4. The machine described by claim. l characterized by having the channels in the front face of the head connected at their outer ends by grooves that extend annularly around the face of the head inside of the closed outer edge.

vLarme/15 5. The machine described by claim l characterized by having its front face which forms the backin surface for an abrasive disk comprised of a closed continuous annular outer section and radiating inner sections xvith channels between said sections7 the faces of Which sections are in the same plane.

6. The machine described by claim 1 characterized by having detachable means at the center of the head adapted to cover the front of the central opening and the inner ends Vof the channels `and mechanically clamp the center .of an abrasive disk held on the face of the head by the exhaustion of air from the head.

Si 'ned at Hartford, Conn., this 15th day of N arch, 1919. v

. WILLIAM A. LORENZ. 

